US 7631503 B2
A combustor for a gas turbine engine having an inner combustor wall and an outer combustor wall with a number of heat shields mounted internally thereto with fasteners. Each combustor wall has an end wall defining a combustor dome with a number of: fuel nozzle openings; impingement air openings; and heat shield fastener openings. Each of the end walls has an overlapping portion with mutually engaging sealing surfaces with the openings within the overlapping portions being aligned in overlapping pairs, where an exterior overlapping portion has at least one of the aligned openings of one overlapping pair being of larger dimension than the aligned opening in an interior overlapping portion.
1. A combustor for a gas turbine engine comprising an inner combustor wall terminating in an inner end wall portion and an outer combustor wall terminating in an outer end wall portion, wherein the inner and outer end wall portions at least partially overlap each other defining a combustor end wall including an exterior overlapping end portion and an interior overlapping end portion, each overlapping end portion having a plurality of impingement air openings, wherein the exterior overlapping end portion has at least one of said openings having a larger dimension than an aligned opening in the interior overlapping end portion defining an aligned pair of impingement air openings.
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The invention relates to cooling of a gas turbine combustor cooling.
The invention relates to combustors for gas turbine engines assembled of an inner and an outer combustor wall with heat shields mounted internally. The combustor walls overlap at the annular dome portion of the combustor which also contains nozzle openings, impingement air cooling openings and openings to permit heat shield fasteners to pass through. The heat shield fasteners can also serve to clamp together the overlapping portions thereby sealing the overlapping surfaces.
An example of such a combustor is described in U.S. Pat. No. 6,497,105 to Stasny.
As the size of the overlapping portions increases, the likelihood of maintaining the seal increase, however interference with openings in the dome for cooling airflow and fuel nozzles increases. Since gas turbine engines and their combustors are assembled or stacked up from many interengaged parts, the compounding effect of manufacturing tolerances for each component results in a cumulative lack of accuracy for the assembled combustor. Small but allowable variations in dimensions within the tolerances set for manufacture, add up to result in a variation in the dimensions and locations of components in the assembled combustor.
Features that distinguish the present invention from the background art will be apparent from review of the disclosure, drawings and description of the invention presented below.
The invention provides a combustor for a gas turbine engine having an inner combustor wall and an outer combustor wall with a number of heat shields mounted internally thereto with fasteners. Each combustor wall has an end wall defining a combustor dome with a number of: fuel nozzle openings; impingement air openings; and heat shield fastener openings. Each of the end walls has an overlapping portion with mutually engaging sealing surfaces with the openings within the overlapping portions being aligned in overlapping pairs, where an exterior overlapping portion has at least one of the aligned openings of one overlapping pair being of larger dimension than the aligned opening in an interior overlapping portion.
In order that the invention may be readily understood, one embodiment of the invention is illustrated by way of example in the accompanying drawings.
Further details of the invention and its advantages will be apparent from the detailed description included below.
As best seen in the detailed view of
Each of the end walls 16, 17 have an overlapping portion the detailed view of which is shown in
As shown in the example of
The exterior overlapping end wall 16 has at least one slotted heat shield fastener opening 21 likewise to accommodate the accumulation of minor alignment tolerances in assembly with the smaller circular openings 21 shown in
Therefore the invention provides slotted or oversized openings 20, 21 in the externally overlapping end wall 16 in alignment with smaller holes 20, 21 in the internally overlapping end wall 17 to accommodate manufacturing and alignment tolerances in assembly, while maintaining the sealing surface integrity of the overlapping end walls 16, 17 clamped and sealed together with the fasteners 15. The size of the slotted or oversized impingement air openings 20 shown in
The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without department from the scope of the invention disclosed. For example, the overlapping portion need not be present in a combustor end wall, but in any portion of the combustor. The combustor liners may be fastened using any suitable means, and need not be fastened by heat shields. Heat shields need not be present at all. Still other changes will be apparent to the skilled reader. Although the above description relates to specific preferred embodiments as presently contemplated by the inventors, it will be understood that the invention in its broad aspect includes mechanical and functional equivalents of the elements described herein.